Automatic-stop control for testing machines



Sept. 7 1926.

I F. D. SMITH, JR

AUTOMATIC STOP CONTROL FOR TESTING wuacmmss I Filed March a, 1926 2 sheets-sheet 1 gnuwnlio'a Spt. 7, 1926. 1,599,254 F.D.sMnH,JR AUTOMATIC STOP CONTROL FOR TESTING MACHINES 3 Filed March a. 1926' 2 Sheets-Sh et 2 4 3 I i I l l l i i I l g l l I I' I l I l I i i Patented Sept. 7,1926.

UNITED s' rA Es 1,599,254 PATENT OFFICE} FRANK D. SMITH, JR, OF WASHINGTON, DISTRICT COLUMBIA.

AU'roMATIc-s'rorooN'rnoL Eon TESTING MACHINES.

Application filed mien s, 1926. Serial No. 93,179.

This invention relates to an automatic stop for tensile testing machines and is designed to stop or to stop and reverse the motion of the machine at the-breaking of the test piece. It can be adapted to machines of either the horizontal or vertical type although the verical type only is shown in the accompanying drawings. The device is especially applicable to the type of machine disclosed in the patent to H. L. Scott Number 1,324,470.

The general operation of the machine consists in clamping a test piece between two clamps, the upper clamp being operatively connected to a. dial and the lower clamp be- 1 ing connected to a ,tension applying screw.

may at present be moved by hand or it may be moved by the bracket on the test screw when a predetermined lower limit is reached. The first method requires the attention of the operator and the second con-' sumes an excessiveamount of time before it operates,'especially if the break occurs at a distance above the lowerlimit stop.

The purpose of this invention, therefore, .is to cause the rod to be moved automatically at the instant of the breakage of the test piece, regardless of the attention of theoperator or where the break occurs. v v

The details of how. this is done will appear in the course of the following decription.

In the drawings, in which'like numerals represent thesame or similar arts:

Figure 1 shows a side View 0 the vertical type of machine with the improvementin use.

Figure 2.1s an enlarge'd .s1de view of one form of my invention.

Figure 3 1s a sect'on'online s 3 of Fig- .ure 2.- i

Figure 4 is a section on line 4-4 of Figure Figure 5 is a detail' of the friction cylinder.

Figure 6 is a detail of the, lever mounting.

Figure 7. shows an electrical modification.

Figure 8 shows a variation of parts of the device shown in Figure 7.

Referring to Figure 1 the-letter A designates the dial portion of the machine; B the lower clamping means and my improvement; and C the driving mechanism for the machine.

In the drawings 10' -is the clamp for the lower portionof the test piece 11. Clamp 10 is connected by means of rod 12 to lever 13 which is pivoted on rod 14 to main support 15 which is carried by screw 16. Support or bracket 15 has a circular opening 17 enabling it to. slide freely upon rod 18. ,An' adjusting screw 19 bears on lever 13 at 20 and limits the movement of .the lever as tension is applied to test piece 11. Lever 13 has an enlarged portion 2121. The enlarged portion consists of 21 integral with lever 13 and 21 removablyfastened to 21" by screws 26.

At suitable positions on rod 18 collars'23a' I and 24 are fastened. When support 15 strikes collar 24 the driving mechanism for serew.16 is stopped or preferably stopped and reversed, and when portion 21 oflever 13 strikes collar 23 the drivingm'echanismis disconnected from screw- 16.. These op-' erations are performed by vertical-reciprocation of rod 18- operating in gear box (L,

but as this forms no part of my invention it will not be further described.

The method of. pivoting 'lever 1 3 is best shown in Figure 6. Trunnion 29 has screw threaded hole 28 to receive screws 34 and thus make it removable from bracket 15.

Adjustment of the lever with respect to rod 18 is obtained by. means of moving screws 34 in slots 33 in bracket 15. v

A spring 30 is provided if desired to aid in the movement of the lever 13 when in op eration. This spring is fastened to lever 13 a at 31 and tobracket 15 at 32. The spring is most desirable in the horizontal typeof machine. v l i v I prefer to cut the cylinder 22 as shown at 22' in Figure 5 to enable it tobe placed about rod 18 and in theholder 21-21 withp out removing the rod. Any suitable materialcan be used for cylinder 22 such as rubber or leather, or portions 35 and 36 may be suitable knurling on the inside of 21-21'.'

I prefer to use a removable cylinder of rubber as shown in Figure 5.

7 y P g S rew 27' the automatic stop may be rendered inoperative to permit specialor fatigue testing. \Vhen screws 27 and 19 are both in contact with lever 13 it is clear that movement of the lever is prevented.

A spring 37.is coiled about rod 18 and 1s freely-movable thereon. In the upper or stop position this spring compresses about an inch and a half before motion ceases. Thus the lever 13 cannot pivot to theright upon starting until after about an inch of travel'and by this time the tension on piece 11 holds lever 13 up.

hole by the limit plug 59. Pin 62 is mou nted on rod 12 and is movable in slot 63 of lever 13. lVhere straight motion of the clamp is not necessary it may be mounted directly on lever 13 as shown in Figure 7. The operation of this modification is as follows:

When tension on test piece 11 is removed due to breakage, the weight of the clamp 10 and if desired, the added tension of spring causes lever 13 to rotate to the right. As

' a result, portions and 36 of cylinder 22 bear frictionally upon rod 18 and carry it downward causing the driving motion to reverse and move bracket 15 and attachments, upward. By means of screw 19, cylinder 22 is prevented from gripping rod 18 on the upward travel. At the top of the journey, holder 21 will strike collar 23 and so stop'the machine, making it ready for the next test. Thus the motion is reversed automatically regardless of where the break occurs.

, When fatigue testing is desired, that is when the piece is to receive a number of tension applications, the machine isrun a distance 'in one direction and is reversed, this being repeated until the piece receives a certain number of tension applications or until a break occurs.- This reversal is per: formed by'the bracket striking the collars, and to give the clamp the necessary rigidity it is best to turn up screw 27 thus'preventing movement. of lever 13.

In the modification shown in Figure 7, an electric means is used to actuate thereversing rod when the test piece breaks. The general structure is the same 's in the previous modificationso an additional de scription will not be given. 'Fastened to 7 switch 44, 45 closes.

lever 13 and insulated therefrom byinsul'ation 38 is one part of a -knife switch 39. The other part, 40, is mounted on the bracket 15 by means of insulation 41. A suitable wiring 42 is connected to switch element 39 and through battery 43 to a switch element 44 mounted on the frame of the the machine. To betterillustrate the positions of rod 18 for various operations, I

have suggested a pointer 49 fastened to the rod. The drawings show a set forhaving screw 16 at a standstill. Raising the rod gives a downward motion to the tension screw and lowering the rod gives an up ward motion. When the rod Switch 39, 40- does not close, however, due to the compression in spring 37 holding lever 13 horizontal. By the time spring 37 ceases to function, .sufli- -cient tension occurs in the test piece and this tension serves to holdthe lever horizontal. When a break occurs, lever 13 pivots to the right and switch 39, 40 closes thus energizing solenoid 47. Rod 18 beis raised comes the core of the solenoid and is pulled down by it, causing a reversal of the driving mechanism, and causing the screw 16 to move upwards. As rod 18 is pulled down switch 44, 45 is opened and solenoid 47 is deenergized allowing bracket 15 to return, without actuating rod 18 on the upward travel until collar 23 is reached.

Afurther modification of the above is shown in Figure 8 in which closed mercury switches are used in order to prevent sparking. Rod'- 18 carries bracket 49 which has roller 50 journalled therein. When the rod is raised, roller 50 raises lever 51, pivoted.

at 52 to the frame, and causes mercur 53 to fill the short leg of sealed tube 54 an make contact between switch elements 44 and 45'. When a break occurs, lever 13 tilts to the right and mercury55 fills short leg of tube 56 making contact between switch elements 39 and 40', which energizes solenoid 47 .as above.

Any of these modifications will operate should the piece slip out of the clamp prior to breakag In case the device is to be used with a hydrauliomachine, rod 18 may be connected to avalve and so arranged as to set the valve in inlet, exhaust-or neutral position.

Many changes are possible without departing from the spirit of the and I limit myself only to the extent of the claims which follow. a

I claim:

1. In a testing machine of the class described, the combination of means for applying tension to a piece of goods, operating means for said tensioning means, control -means for said operating means, a bracket mounted on said tensioning means,-and a lever to operativelye connect said bracket to said control means.

2. In a testing machine the combination of means for applying tension to a piece of goods, operating means for said tensioning means, control means for said operating means,a' bracket mountedon said tensioning means, and a .lever mounted on said bracket to operatively connect saidbracket to said control means. 3. In a testing machine, the combination of means for applying tension to a piece of goods, operating means for said tensioning means, control means for said operating means, a bracket mounted on said tensioning means, and a lever removably and adjustably mounted on said bracket to operatively connect said bracket to said'control means.

4. 'In a testing machine, the combination of means for applying tension to a piece of goods, operating means for said tensioning means, control means for said operating means, a bracket mounted on said 1781151011- lng means, and a lever pivotally mounted on said bracket to operatively connect said bracket to said control means.

5. In a testing machine, the combination of means for applying tension to a piece'of goods, operating means for said tensioning means, control means for said operating means, auxiliary means mounted on said tension applying means to actuate said control means and means to maintain said auxiliary means disconnected from said coritrol means when the tension member moves in one direction.

6. In a testing machine, the combination of means for applying tension to a piece of goods, operating means for said tensioning means, control means for said operating means, auxiliary means mounted on said tension applying means to actuate said control means, and an adjustable screw tomaintain said auxiliary means disconnected from said control means when the tension member moves in one direction.

' 7. In a testing machine, the combination of means for applying tension to a piece of goods, operating means for said tensioning means, control means for said-operating means, auxiliary means mounted on sald ,tension applying means to actuate said control means and means to hold said auxiliary means disconnected from said control means invention, 1

when the limit of movement of the tension member in one direction has beenreached.

8.- In a testing'machine, the combination of means forv applying tension to a piece of goods, operating means for said tensioning means, control means for said operating means, auxiliary means mounted on said tension applying means to actuate said control means, means to hold said auxiliary means disconnected fromsaid control means when'the limit of movement of the tension member in one direction hasbeen reached, and means tomaintain said disconnected relation during a small tensioning 'movement of said tensioning means.

9. The structure as set forth in claim 8,

and said last named means being'inoperat1ve after said small tensioning movement has taken place.

10. In a testmg machine, the combination of means for applying tension to apiece of goods, ope-rating means for said tensioning means, control means for said operating means, 'auxlllary means mounted-on said tension applying means to actuate said con:

trol means, means to hold said auxiliary means disconnected from said control means when the limit of movement of the tension member in one direction has been reached,

and a spring to maintain said disconnected relation during a small tensioning niovement'of the tension applying means.

11. In a testing machine, the combination of means for applying. tension to' a piece of goods, operating means for said tension .ing means, control means for said operat-- mg means, and auxiliary means set in opercontrol means to said tension applying means; I a 4.

12. In a testing machine, the combination of means for applying tensionto apiece of goods, operating means for said tensioning, a reciprocable-rod to control said operatlng means, a bracket'mounted on said tensioning means, a lever pivotally mounted on said bracket, said lever being controlled at one end by a clamp which holds the goods, the opposite end of-the lever comprising an enlarged portion with an aperon said rod, when there is tension in the I goods but small enough to bind on said rod 'ation upon the removal of tens-ion iirthe piece of goods to operativ'ely connect 831d tur e therein which surrounds said rod, said aperture belng of such size as to slldefreely 15. The structure of claim 12 and a cylinder mounted in said enlarged'portion.\

16. The structure of claim 12 and a yield ing cylinder mounted in said enlarged portion.

17. Thestru'cture of claim 12 and a rubber cylinder mounted in said enlarged portion.

18. The structure of claim"12 and a cylinder; mounted in said enlarged port-ion, said aperturehaving circumferential grooves and said cylinder having ridges to fit said grooves. V i

19. In a testing machine, the combination of means for applying tension to a piece of goods, operating means for said tensioning means, control means for said operating means, auxiliary means to actuate said control means, a clamp mounted to control said auxiliary means and means to restrict the motion of the clamp to a straight line.

20. In a testing machine the combination of means for applying'tension to a piece of goods, operating means for said tensioning means, control means for said operating means, abracket mounted on said tensioning means, auxiliary means to operatively connect said bracket to said control means, a clamp to control said auxiliary means, a rod on said clamp and whole in said bracket, said rod being mounted in said hole.

' 21. In a testing machiiie having a shift rod with limit collars to reverse and stop a tension, applying 'means and having a bracket on said tensioning means, movable on the shift rod to engage said collars;

- auxiliary means to operatively connect the bracket to the shift rod when the tension in the piece is removed.

22. The structure of claim 21 and means to mount said auxiliarymeans on the bracket.

23. Thestructure of claim 21 and means to prevent said bracket being operatively connected When the tension'in'g'means moves in a predetermined direction.

24. The structure of claim 21 and means grooves.

32. In combination, a lever, an apertured to render said auxiliary means completely inoperative. r

25. The structure of claim 21 and means to render said auxiliary means inoperative during a small initial tensioning movement of t he tensioning means. i 4

26. The structure of claim 21 and a spring loosely coiled about the shift rod, said spring rendering said auxiliary means inoperative during a small initial tensioning movement of the tensioning means.

27. Thestructure of claim 21 andra lever pivotally mounted on the bracket, said lever being controlled by a clamp for the goods at one end and having an enlarged portion at the opposite end, said enlarged portion having an aperture freely. movable on the rod when the lever is in one position, said aperture being of such size as to bind on the rod With limit collars to reverse and stop a tension applying means and having a bracket on said tensioning means movable: on the shift rod to engage said collars; a lever, means to mount said lever on the bracket, said lever being controlled by a clamp at one end and having an enlarged portion With an aperture adapted to surround the rod, and a cylinder removably mounted in said aperture.

29. The structure of claim" 28 and said cylinder being made of a yielding material. .30. The structure of claim 28 and said cylinder being made, of vulcanized rubber.

31. The structure of claim 28 and said aperture having circumferential grooves, and sald cylinder having ridges to fit said portion at one end of said lever, a trunnion pivoted to said lever and adapted to be mounted on a bracket, and means to connect a clamp to saidlever opposite to said apertured end, all for the purpose set forth.

FRANK D. SMITH, JR. 

